LicenseCore.Lib

Hardware-bound license validation for .NET applications.

Drop into any ASP.NET Core app with two lines of code. Cross-platform (Windows, Linux, macOS). All cryptographic defaults baked in — works without any appsettings.json configuration.

Quick start

dotnet add package LicenseCore.Lib

In Program.cs:

using LicenseCore;

if (LicenseBootstrap.HandleCliFlags(args)) return 0;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddLicenseValidation();    // startup + 24h re-check

var app = builder.Build();
app.UseLicenseGate();                        // returns 503 if invalid

app.MapGet("/", () => "Hello");
app.Run();
return 0;

How it works

Customer machine                              Vendor server
─────────────────                             ─────────────

  YourApp.exe --machine-info
      ↓
  license_data.json (hardware fingerprint)
      ↓
      send to vendor    ────────►   LicenseCore.exe generate
                                         ↓
                                    license.lic
      receive license.lic ◄────────  send back

  Drop license.lic next to YourApp.exe
      ↓
  YourApp.exe
      ↓
  LicenseValidator validates on startup + every 24h
      ↓
  UseLicenseGate middleware returns 503 if invalid

CLI flags handled automatically

Configuration

All defaults work out of the box. Override only what you need.

Option 1: Programmatic (recommended)

builder.Services.AddLicenseValidation(opts =>
{
    opts.LicenseFilePath = "C:/etc/yourapp/license.lic";
    opts.RecheckInterval = TimeSpan.FromHours(6);
    opts.SupportContact  = "help@yourcompany.com";
    opts.BypassPaths     = new() { "/health", "/admin", "/api/public" };
});

Option 2: appsettings.json

{
  "LicenseValidation": {
    "LicenseFilePath": "license.lic",
    "RecheckInterval": "06:00:00",
    "SupportContact": "help@yourcompany.com"
  }
}

Option 3: Environment variables

LicenseValidation__LicenseFilePath=/etc/yourapp/license.lic

What validation checks

1. Anti-tamper: system clock didn't move backward beyond the tolerance (default 1 day)
2. File integrity: license.lic decrypts cleanly
3. Signature: HMAC-SHA256 signature verifies against vendor's key
4. Hardware binding: machine_id, system UUID, CPU ID, disk ID all match current machine
5. Expiry: not past the expiry date

Any failure flips LicenseValidator.IsLicenseValid to false, and UseLicenseGate() starts returning 503.

Built-in static state (for UI / diagnostics)

LicenseValidator.IsLicenseValid     // bool
LicenseValidator.LastError          // string
LicenseValidator.LastCheckedUtc     // DateTime
LicenseValidator.DaysRemaining      // int
LicenseValidator.Customer           // string?
LicenseValidator.Expiry             // string? (YYYY-MM-DD)

Bypass paths

/health and /admin/license are always allowed through the gate by default, so health checks and support diagnostics keep working when the license is invalid.

Default 503 response

{
  "error": "Service unavailable",
  "reason": "License has expired",
  "last_checked": "2026-05-24T14:00:00Z",
  "contact": "support@yourcompany.com"
}

Cross-platform hardware identifiers

License

Proprietary — internal use by YourCompany.